Fluorescent light fixtures have been a popular form of lighting for many decades. A fluorescent lighting fixture includes one or more fluorescent tubes, with each tube having an end cap on each end of a generally cylindrical glass tube. Within the tube is confined a mixture of gases which cause a coating on the inside of the tube to fluoresce when power is conducted through the gas from one end of the tube to the other. The end caps of the fluorescent tubes fit into an electrical connection on each end, with a tombstone type connection being a typical example. Other types of connections are also possible but all would have end caps with electrodes at the end which connect to a power source.
The typical fluorescent fixture also includes a box or luminary in which the tubes are enclosed, and typically a reflector or diffusion plate of some type or both. A typical diffusion plate may be a panel of plastic with diamond or pyramid shape projections on one surface of the plastic. This helps to spread the light from the fluorescent tubes into a wide area in a room. The luminaries are typically a metal box which is mounted in a false ceiling of a room, so that the diffuser plate which forms one side of the luminary is flush with the ceiling. Obviously there are a huge variety of other types of fluorescent fixtures, but this is a description of a very common type.
Lighting systems based on LED light sources are a fairly new technology in the lighting field. LED's are desirable because they have an extremely long life, and they use far less power than fluorescent tubes of equivalent output. However, the installed base of fluorescent light fixtures is huge, and removing every fluorescent light fixture would be an incredible expense. What is needed is an LED light which replaces the fluorescent tubes in a typical fluorescent luminary, which does not require replacement of the luminary itself or other components of the fluorescent light fixture.